Actually JR's ownership percentage has reportedly been listed at 5% or so but that is still enough for him to be in day to day control as per agreement with the other owners for putting together the original deal to buy the club from Bill Veeck.

Because he is in day to day control (which is also written into his contract by the way which states he can do as he wishes without having to consult the other minority owners on baseball matters) he has the right to sell to whom he chooses to first before any other individual or company can get involved.

Lip

The team is set up as a Limited Partnership. This isn't ground breaking in the business world. There is a board of directors who have very little input on the day to day things.

As for selling the team, I believe he can sell to whom he wants but he is obligated legally to get the best deal possible for his partners. He can't go sell the team to his son for $1 or anything like ridculous like that.